1. Field of the Invention
This invention relates to air-operated diaphragm brakes used with air brake systems on vehicles such as trucks. More particularly, the invention relates to an adjustable apparatus for mounting an air-operated diaphragm brake to a vehicle whereby the pneumatic ports may be readily adjusted to a preselected position during installation of the brake.
2. State of the Prior Art
A typical air brake system for a vehicle such as a bus, truck or the like includes separate brake means such as a brake shoe and drum of the vehicle wheels. The brake shoes are actuated in one direction to apply the brakes and in the other direction to release the brakes. The brake means may serve as both service and emergency brakes, and individual brake actuators are located adjacent the wheels for actuation of the brake means.
A typical brake actuator includes a service brake actuator for applying and releasing the brakes in response to delivery and exhaust of compressed air. Often, a spring brake actuator is disposed in tandem with the service brake actuator. The spring brake actuator uses the force of a strong compression spring to operate the tandem mounted service brake actuator and to apply the brakes when air in a spring chamber is reduced below some predetermined level. Air may be reduced in the spring brake actuator under the control of the operator in the manner of a parking brake, or automatically in emergencies such as the failure of portions of the brake air system.
Thus, in a typical tandem air-operated diaphragm spring brake system, two pneumatic ports are provided, one for the service brake, and one for the spring or emergency brake. The service brake chamber and spring brake chamber are typically separated by an adapter housing which forms a wall between the two chambers, and the pneumatic ports are provided in the adapter housing.
It is known to form the spring chamber by securing a spring housing to a spring side of the adapter housing with a permanent, fluid-tight seal. The seal may be formed by providing the spring housing with an integral annular shoulder and an extended lip portion which is roll formed or swaged over an annular flange of the adapter housing. Alternatively, the spring housing may have an annular flange which is clamped to the adapter housing by a separate clamp band. A spring diaphragm is interposed between the annular flange and the annular shoulder to form the fluid-tight seal. Similarly, the service brake housing may be secured to the adapter housing with a similarly configured permanent formed or clamped seal. However, brake actuators of the this construction are typically mounted to vehicles by means of bolts or studs projecting from the end of the service brake housing. When the service brake housing is permanently sealed to the adapter housing, the mounting studs are fixed in orientation with respect to the pneumatic ports extending from the adapter housing. Thus, when the brake is mounted to the vehicle, the pneumatic ports may be positioned where it is difficult or impractical to connect air conduits to the pneumatic ports. In other words, different vehicles require different orientations of the mounting studs with respect to the pneumatic ports.